Ok do this:

After u had made the line:

Step1: leave teh line as it is. DO NOT MAKE SELECTION. I mean leave the lines in "Path" form, now choose the brush tool.


Step2: choose a soft round brush of say 2 px.


Step3: choose the color that u want

Step4: Now select the pentool again and on the lines Right Click>>Stroke Path.


Step5: In the Selection box that appears choos Brush


Step6: Now on the line again RightClick>>Delete Path.


And bingo ur done,


I hope this is what u were asking for